![]() ![]() I think this is the most effecient way to set deck height. I like Mike's assesment on the shim under the cylinders instead of the top. I think that he thinks that all other machinists are hacks and that they use drill presses as milling machines to fly cut the head. ![]() Nsracing has been around the forums for a while, it's just his way of saying that he feels that he does the job right. It is being done by a damn good shop that have been doing VW's for decades. I don't know where that comment came saying I was doing this myself with a drill. The edge of the stud holes show in the head's piston bore and I wanted to make damn sure it is sealed. These Okrasa heads have been opened up to there max to run the 83mm Porsche pistons. They stated that they run zero deck height on all their race engines and adjust the CR with copper gaskets. The shop selling the gaskets is a VW race shop. They also mentioned that it would reduce the chance of carbon building up on the piston edge and interfering with the head gasket. My deck height that I have would not allow the piston to hit anyway but this is a little added insurance. They recommended that I angle cut the edge of the piston. You would basically add whatever the total cc's are from the deck and the combustion chamber and have the step made deep enough to cover both, since running zero deck yields zero cc's. I think it would actually have to be a little deeper to maintain the correct cc's. it would probably need to be a judgement call.Īnother option would be to flycut a step in the head. although this wouldnt compensate for the hot squish that will happen when the head expands. I guess if i was going to get that close when using copper gaskets, i would probably bolt the case together, then bolt the cylinders and heads on one side and torque them down and then go thought the other side and see how the gaskets squish. The only time I have heard people having problems is when they have been re-used. Even great cut heads can leak slightly because of imperfections in the jug surface and or head surface, but not with copper gaskets. My experience has always been with the pre-made gaskets for 94mm jugs - I can't lie, I can only recommend them. Hence my original statement of "make double sure they fit snugly in the head bores and clear the pistons properly". Not that it doesn't happen, but it doesn't seem likely to interfere with the piston travel if they are properly cut. I have used four different sets of copper gaskets so far and they have all been slightly narrower than the jugs themselves - after being compressed by torquing the head studs. Probably wouldnt be a real problem, but it would always be in the back of my mind. If you try the copper head gaskets, and they are just slightly off or tend to squeeze in, you may need to trim the top of the piston down to make sure if you extend past the intended deck, you dont hit a wall of copper with the edge of the piston. He asked which would be best, shims or a head gasket.ĬoolairX2, I think whatever is most convenient for you will work fine.ĭepending on your piston configuration, i think i would lean toward new shims under the cylinders. Just what does flycutting and a drill press have to do with adjusting his deck height? Nsracing wrote: If you flycut the head beautifully like it is supposed to be done, you will not need a gasket. It is all up to you what you are willing to put up with on sloppy machining. At least that is what I use to flycut my case and heads. It takes a $1200 boring/flycutting head to do this operation. If you flycut the head beautifully like it is supposed to be done, you will not need a gasket.īut what does a drill press contraption do to the heads other than rough it some more? And you really expect that to seal? I would just make double sure they fit snugly in the head bores and clear the pistons properly if you are using them to compensate for a too high deck height. I have always had good luck with them sealing the cylinder properly (knock on wood), even though I have heard a couple of people say that they didn't care for them. Given that I was leaning towards B but have never used custom head gaskets. These are custom sized P&C's so they would have no head gaskets at all unless I get some made. So basically I have the Pistons reaching the top of the cylinder maybe a few thou. Now I did mess up when I ordered the spacers and forgot to add the. Ok I am assembling a 36hp Okrasa with 83mm Porsche 912 Mahle P&C's. View original topic: Copper head gaskets or cylinder spacer question. ![]() Forumsįorum Index -> Performance/Engines/Transmissions -> Copper head gaskets or cylinder spacer question. :: View topic - Copper head gaskets or cylinder spacer question.
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